IEC 172 |
| Sudip Mukhopadhyay, Ashutosh V. Joshi, and Yoel Sasson. Applied Chemistry, Hebrew University, Givat Ram Campus, Jerusalem, 91904, Israel |
| The syntheses and utilization of biaryl compounds is a subject of considerable contemporary interest as they represent important building blocks for numerous agrochemicals, pharmaceuticals, and for a large number of natural products of varied structure, biological activity, and biosynthetic origins. Also, biaryls are the structural units of the chiral skeleton of many of the asymmetric catalysts. Besides, stoichiometric classic general Ullmann, Suzuki, and Stille coupling reactions, Pd-catalyzed reductive coupling of haloaryls has been obtained the attention of many researchers. The reductive coupling of haloaryls benefits from simple reactor design, easy catalyst separation, and recycling. There is an incentive to search for different heterogeneous catalyst systems. Thus, reductive coupling of halobenzenes and substituted haloaryls to the respective biphenyls is effected in water with good selectivity, using a reducing agent such as formate salts and a base, NaOH in the presence of catalytic amount of PEG-400 and 5% Rh/C catalyst at 115 C temperature. The catalyst can be efficiently recycled. The competing reduction reaction is minimized with proper alteration of the operating conditions. The role of temperature, catalyst loading, reducing agents, base, and PEG-400 are studied. The reaction follows a zero order kinetics. |
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General Poster Session
5:00 PM-7:00 PM, Tuesday, March 25, 2003 Convention Center -- Hall G, Poster
Sci-Mix
Division of Industrial and Engineering Chemistry |